Liver disease often associated with superficial necrolytic dermatitis

Clinical history:
The dog presents today for a worsening skin disease that appears to be a necrolytic process occurring in the upper layers of the skin. The dog has had a history of several episodes of skin infections that have responded to antibiotics and medicated shampoo. Last month, the dog re-presented with a severe rash of the ventral abdomen and was treated with trimethoprim-sulfa drug combination for 14 days and a requested refill was done for an additional 10 days. No response in skin lesions has occurred. Last week, the skin disease was the worst seen and the affected areas were suspicious for an immune-mediated skin disease.

Laboratory results:
A complete blood count, serum chemistry profile and urinalysis were performed and are outlined in Table 1. Additional results from an ACTH stimulation test include are in Table 2:

Radiographic review:
Survey thoracic and abdominal radiographs were done. The thoracic radiographs are normal. The abdominal radiographs show an enlarged liver and/or spleen.

Table 2:

Ultrasound examination:
Thorough abdominal ultrasonography was performed. The dog was positioned in dorsal recumbency for the ultrasonography. The ultrasound images provided are from this dog's liver.

My comments:
The liver shows an increase in mixed echogenicity with multiple hypoechoic lesions scattered throughout the liver parenchyma. Note the characteristic "Swiss cheese" pattern in the liver parenchyma. The gallbladder is mildly distended, and its walls are not thickened or hyperechoic.

Photo's 5 & 6

The gallbladder does contain some sludge material. The spleen has uniform echogenicity - no masses noted. The left and right kidneys are similar in size, shape and echotexture. No masses or calculi were noted in either kidney. The urinary bladder is distended with urine and contains some urine sediment material - no masses or calculi noted. The stomach wall is normal.

Case management:
In this case, hepatocutaneous syndrome is the clinical diagnosis. The following concise summary is provided by Dr. Rod A. W. Rosychuk, diplomate of ACVIM (internal medicine), Colorado State University, Fort Collins, Colo., and was presented at the 18th Annual ACVIM Veterinary Medical Forum in Seattle in 2000.

Hepatocutaneous syndrome
Hepatocutaneous syndrome, also known as superficial necrolytic dermatitis or metabolic dermatosis is an uncommon dermatosis seen in dogs and has been described rarely in the cat.

Photo's 7 - 12

Superficial necrolytic dermatitis in dogs has been associated with hepatopathies in most cases. The most common hepatopathy is an idiopathic hepatocellular collapse. Other findings may include cirrhosis, hepatopathy secondary of ingestion of mycotoxins, and hepatopathy possibly associated with primidone or phenobarbital administration.

Non-hepatic associations have included glucagon-producing pancreatic adenocarcinoma, hyperglucagonemia and glucagon-secreting liver metastases, and gastric carcinoma. Affected dogs may become diabetic, although the cause of the diabetes mellitus is not known. Idiopathic pancreatic atrophy has been noted.

Clinical signs and laboratory findings
Superficial necrolytic dermatitis is generally seen in middle-aged to older dogs - average being 10 years old. Males are more commonly affected. The history of skin lesions may span weeks to several months and may wax and wane. Skin lesions are usually noted to first affect the feet - interdigital erythema, crusting, erosions, hyperkeratosis, fissuring of footpads. Toenail loss has been noted.

Skin lesions may become pruritic and painful. Symmetric erythema, alopecia, crusts, and erosions/ulcers may be noted around the mouth, muzzle, eyes, hocks and elbows, pressure points, vulva and scrotum. Bulla-like lesions may be noted. Bullae appear to represent necrotic epidermal tissue and are not usually filled with appreciable amounts of purulent material. The skin lesions are prone to secondary staphylococcal and Malassezia infections, secondary candidiasis and dermatophytosis. The importance of the underlying disease in the predisposition to these infections is the observation that therapy for the underlying disease may result in the spontaneous resolution of the secondary infections.